apparent in the neotropical species surveyed. Spongy parenchyma varies from compact with 
small air spaces to loose and containing conspicuous lacunae. Oil cells are usually present, but 
sometimes scarce. They can be in both palisade and spongy chlorenchyma (figure 3), but few 
species have them apparently restricted to palisade tissue (C. formicarium). Oil cells are 
commonly ellipsoid, and the same size as surrounding cells when in the palisade layers. When in 
the spongy chlorenchyma they tend to be spherical and bigger than neighboring cells. Midvein in 
cross sections show usually the vascular tissue arranged in a slightly crescent arrangement (figure 
3); xylem adaxial and phloem abaxial. Few species present a rather flat view of the vascular 
tissues (C. bractefoliaceum, C. chiapense, C. hartmanii, C. haussknechtii, C. leptophyllum 
(figure 3), C. uninervium (figure 3), C. velvetii). Sclerenchyma normally surrounds the whole 
vascular bundle, and collenchyma frequently is adjacent to both upper and lower sides of 
collenchyma. There is only one species (C. napoense) where vascular tissue appeared fragmented 
in several separate bundles in the midvein. Secondary and tertiary veins are mostly with 
transcurrent sclerenchyma (figure 3); except in C. costaricanum (figure 3), and C. neurophyllum. 
View of cross sections at the level of domatia did not show difference compared to that of 
normal leaf tissue, except for the presence of hairs on the borders and sometimes also on the 
walls of those structures. It is interesting to note that, when domatia are distinct in pubescent 
leaves, hairs do not arise from the bottom surface. Contrary to what was found by Petzold 
(1907), crystals were not seen in any of the species in cross sections, but it might be found that 
they are conspicuous only in epidermal peelings, which were not prepared for all the species in 
this study. 
When contrasted to what was previously known about the leaf anatomy of some species 
26 
